Automatic cycling control for continuous miners



Oct. 3, 1961 J. R. BOUILLE 3,002,732

AUTOMATIC CYCLING CONTROL FOR CONTINUOUS MINERS Filed May 3, 1954 4Sheets-Sheet 1 llllul C s MW dorzzeg.

Oct. 3, 1961 J, R. BOUILLE 3,002,732

AUTOMATIC CYCLING CONTROL FOR CONTINUOUS MINERS Filed May .'5, 1954 4Sheets-Sheet 2 y wwf,

Oct. 3, 1961 J, R, BQUILLE 3,002,732

AUTOMATIC CYCLING CONTROL FOR CONTINUOUS MINERS Filed May 3, 1954 4Sheets-Sheet 3 plu.

Milli 6220 re? gy.

linnn J. R. BOUILLE 3,002,732

AUTOMATIC CYCLING CONTROL FOR CONTINUOUS MINERS 4 Sheets-Sheet 4 Oct. 3,1961 Filed May s, 1954 fwenonnited rates This invention relates to anautomatic cycling control mechanism and more particularly to anautomatic cycling control for a continuous miner for automaticallycontrolling the movements of the attacking and disintegrating head ofthe miner during the mining operation.

In the copending application Serial No. 312,876, now Patent No.2,939,692, iiled October 3, 1952, owned by the assignee of the presentinvention, there is disclosed a continuous miner especially designed foruse in the longwall mining of coal or similar minerals `:from a solidmine vein and in this miner, a vein-attacking and disintegrating head orjib is mounted on a mobile base for rectilinear back and forth movementsand for swinging movement in vertical planes to eiect tearing away anddisintegration of the mineral. The attacking and disintegrating head,when in lowered position, may be moved rectilinearly longitudinallyrelative to the base to effect sumping of the head into the mine vcin atthe oor level, then the head may be swung upwardly to remove the mineralbetween the lio-or and the roof, thereafter the head may be retractedrectilinearly from the face at the roof level to complete the cut, andnally the head may be returned to its initial lowered position. Thesevarious operations in the miner above described are effected separatelyunder manual control, and the present invention contemplate improvementsover the miner above referred to in that the sumping, swinging,retracting and lowering operations of the attacking and disintegratinghead are eiected automatically in a definite sequence and without manualintervention, simply l`by pressing a starting push-button or knob on themachine, thereby to speed up the mining cycle.

An object of the present invention is to provide an improved continuousminer having improved control means for the attacking and disintegratinghead or jib. Another object is to provide an improved automatic cyclecontrol for a mining apparatus. Yet another object is `to provide animproved automatic cycling control mechanism for the sumping, swinging,rctracting and lowering movements of the attacking and disintegratinghead of a continuous miner. A further object is to provide an improvedautomatic cycling control for the iluid actuated devices of the minerand embodying coacting mechani cally and pressure uid actuated controlvalves. A still further object is to provide an improved control valvedevice actuated by the pressure in the jib-lifting cylinder forautomatically controlling operation of the retracting cylinders for theattacking and disintegrating ead. `Yet another object is to provide aiiuid actuated vcntcontrol valve for the head swing cylinder whereinsaid valve is held open by the pressure in the swing cylinder as aresult of the weight of the head which causes gravity swing of the headtoward its `lowered position, said pressure being dissipated when thehead assumes its lowered position so that `the control valveautomatically closes. These and other objects and advantages of theinvention will, however, hereinafter more fully appear.

In the accompanying drawings there is shown for purposes of illustrationone form which the invention may assume in practice.

In these drawings:

FIG, 1 is a side elevational view of a continuous miner Patented ct. 3,i961.

fifi

in which an illustrative form of the invention is incorpolaled.

rlG. 2 is a central longitudinal vertical section taken Anon the minershown in FIG. 1.

FIG. 3 is an enlarged fragmentary plan View of the rearward portion ofthe miner, with parts shown in horizontal section to illustrate detailsof the automatic cycling control.

FIG. 4 is an enlarged cross section taken on line 4--4 of FIG. 3.

FIG. 5 is a detail longitudinal vertical section taken on line 5 5 ofFIG. 4, showing the rotary pilot valve and its associated control cams.

FIG. 6 is a View similar to FIG. 5, showing parts in differentpositions.

FIG. 7 is an enlarged detail plan view of the controls shown in FIG. 3,with part of the base frame shown in section.

FIG. 8 is a diagrammatic side View with the miner in operating positionin a mine and showing the different positions of the attacking anddisintegrating head during the mining cycle.

FIG. 9 is a diagrammatic View of the hydraulic iiuid system.

FIG. 10 is a schematic longitudinal section taken through the liuidactuated, pilot operated, four-way valve.

FIG. 10a is a detail section taken on line lila-lila of FIG. 10.

FIG. 11 is a schematic longitudinal section taken through the camoperated two-way pilot valve.

FiG. l2 is a schematic section taken through the rotary four-way doublepilot valve device.

FlGS. 13 and 14 are cross sections taken onlines 1.3- i and E14-14 ofFIG. 12.

FIG. l5 is a schematic longitudinal section taken through the unloadingfluid actuated valve device for the shear cylinders.

FIG. x16 is a longitudinal section taken through the fluid actuatedpressure relay valve.

In this illustrative embodiment oi the invention, as shown in thedrawings, the improved automatic cycling control is associated with acontinuous miner, generally designated 1, especially designed for use inthe longwall mining of coal or similar minerals although, evidently, theautomatic cycling control may be associated with miners of other types.

The continuous miner, as disclosed in the copending application SerialNo. 312,876 above referred to, includes a mobile base Z adapted totravel over the floor or pavement of a mine and carrying a frame 3 onwhich a support 4 is guided for back and forth rectilinear longitudinalmovements with respect tothe base frame. Pivotally mounted on thissliding support 4, at 5, is a vein-attacking and disintegrating head orjib 6, swingable in vertical planes with respect to the sliding supportand the base frame. The attacking and disintegrating head includes aswingaole head or jib frame 7 having a series of disintegrating chains 3guided for circulation in vertical orbits about the head or jib frame.Arranged longitudinally of the base frame 3 are parallel, double-acting,sumping and retracting fluid cylinders itl (FIG. 2) which `containreciprocable pistons 11 having forwardly extend- `head may swingdownwardly from a raised position (FIG.

l) at a controlled rate to bring the outer end of the head to the ilooror pavement level, as indicated at A in FIG. 8, and when fluid isproperly supplied to the sumping cylinders it? the support 4 may be slidrectilinearly forwardly relative to the base to sump the outer portionof the head into the mineral of the mine vein to the position indicatedin dotted lines at B in FIG. 8. When pressure fluid is supplied to thelower ends of the bores of the jib lifting or shear cylinders 15, theattacking and disintegrating head may be swung upwardly in verticalplanes about its pivot 5 to bring its outer portion to the roof level,as indicated at C in FIG. 8, and when pressure iluid is supplied to theopposite ends of the retracting cylinders the head may be retracted fromthe mine vein at the roof level to the position indicated at D in FIG.8. When iluid is again vented from the lower ends of the cylinders 15,the head may swing downwardly back to its initial position at the floorlevel. Thus, by sumping the attacking and disintegrating head into themine vein at the floor level, by swinging the head upwardly in verticalplanes between the floor and roof and by retracting the head from themine vein at the roof level, a wide vertical segment of mineral may bedislodged from the mine vein and between each operating cycle the mobilebase may be advanced toward the face of the mine vein to a new positionand the sumping, swinging, retracting and lowering cycle may berepeated, all as is fully disclosed in the copending applicationmentioned above. The dislodged and disintegrated mineral may be conveyedrearwardly over the top of the head by the rearwardly moving upper runsof the disintegrating chains and the disintegrated mineral is dischargedfrom the head onto a transverse conveyor 2i) which conveys thedisintegrated mineral laterally to discharge. During the operating cycleof the head, the base may be held stationary by an upright holdingcolumn or jack device 21 which includes a vertical cylinder 22containing oppositely moving ypistons 23 and 24 having the outer ends oftheir piston rods acting against the oor and roof of the mine. Since thedetail structure of the continuous miner does not per se enter into thepresent invention other than its manner of cooperation With the improvedautomatic cycle control, further detailed description of the structureand the mode of operation thereof is herein deemed unnecessary.

Now referring to the improved automatic cycle control mechanism, it willbe noted that, as shown diagrammatically in FIG. 9, conventional motordriven pumps 29 and 30 are mounted on the base frame 3, the pump 29having relatively small capacity or volume and the pump 30 havingrelatively large `capacity or volume. The suction sides of these pumpsare connected by conduits 31 and 32 respectively to a duid tank orreservoir 33 which may contain a liquid such as a light oil. Thedischarge side of the small capacity pump 29 is connected by a conduit34 to a conventional pressure reducing valve device 35 and a conduit 36leads from this latter valve device to a conventional rotary controlvalve device 37 having an operating handle 38. This control valve device37 may be similar to that shown in FIG. l2 and is positionable betweenautomatic and manual controlling positions; and in the latter positioncontrol of the cutting cycle of the miner may be eiected manually. Thevalve device 37 has usual return conduits leading back to the tank 33and leading from the valve device 37 is a conduit 39 connected to aconventional starting valve device 40 having a push-button or actuatingknob `41. This likewise has a usual return conduit 42 leading back tothe tank 33. A conduit 43 leads from the valve device 40 to aconventional pilot operated four-way valve device 44, shown in detail inFIG. l0. As shown, this valve device comprises a casing 45 having a bore46 containing a reciprocable three-spool valve 47 of the fluid actuatedtype. The valve casing has usual ports to which the various conduits areconnected in the manner shown, and a return conduit 48 communicates withexhaust grooves 48' (FIGv 10a) in the walls of the valve casing bore andleads back to the tank 33. A conduit 49 communicating with the conduit39 leads to a conventional valve device 50 which is of the balancedplunger, cam-operated two-way type, shown in detail in FIG. l1. Thisvalve device has a casing 51 provided with a bore 52 in which a plungervalve 53 is reciprocable and a coil spring 54 urges the ,valve in anoutward direction. Journaled at the outer end of this valve is a roller55. The slidingsupport 4 carries a shiftable frame 56 near its upperportion, as shown in FIG. l and this shiftable frame is actuated by thepistons 11 of the sumping and retracting cylinders, and carries a cama57 which is engageable with the roller 55 of the plunger valve forholding the latter in depressed position until?. forward movement of thesliding support 4 is initiated, as `will later be explained. The casing51 of the valve 50 is secured to a transverse vertical plate 58 of thebase frame. Leading from the casing of the valve device 50 are conduits59 and 60, and the conduit 59 communicates with the conduit 43 while theconduit 60* leads to a central port 60 of the casing of the valve device44. A return conduit 6-1 leads from the valve-casing back to the tank33. The return conduit 48 may connect the conduit 60 back to the tank33.

The discharge side of the large capacity pump 30 is connected by aconduit 62 to the pressure passage of the valve box 63 of a conventionalcontrol valve mechanism suitably mounted on the base frame 3, in amanner similar to that of the copending application Serial No. 312,-876, mentioned above. The discharge passage of this valve box isconnected by a return conduit 64 back to the tank 33. This valve box hasa usual relief valve mechanism to prevent an overload in the uid systemand is formed with parallel boresl containing conventional slide valvesof the balanced spool type. These valves may be held in a conventionalmanner in central neutral position as by coil springs and may be shiftedin one direction or the other to effect control of the various uidoperated devices of the miner, and two of the valves are designated 65and 66 which respectively control the uid supply to and the exhaust fromthe sumping and retracting cylinders l0 and the jib lifting or shearcylinders i5. As shown in FIG. 9, the slide valves 65 and 66 may befluid actuated and pistons 67 reciprocable in cylinders 68 and 69respectively have piston rods 70 connected to the stems of the valves 65and 66. The valve stems also have manual actuators 7d. which may be usedto shift the valves when the automatic cycling control is cut out by thevalve device 37 and the cylinders 63 and 69 are vented. Communicatingwith the bore of the casing of the valve device 44 are conduits 73 and74 leading to the opposite ends of the operatingV cylinder 68 for theslide valve 65, while leading to the opposite ends of the operatingcylinder 69 for the slide valve 66 are conduits 75 and 76 and theconduit 75 leads to the starting valve device 37, while the conduit 76leads to a conventional rotary four-way double pilot valve device 77.This valve device is shown in detail in FIGS. l2, 13 and 14 and includesa casing 78 having a bore 79 containing a rotary double valve 80provided with an operator 81 provided with spaced arms 82 and 83. Thisvalve is cross ported at 80 and grooved at 81', as shown, and the valvecasing has usual ports to which the several conduits are connected andusual return conduits 84 and 85 leads from the valve device back to thetank 33. The shiftable frame 56 carries longitudinally spaced cams 86and 87 which are effective to rotate the valve 80 upon engagement withone or the other of the arms 82, 83 in the different positions of thepistons 11 of the sumping and retracting cylinders 10, as will later bedescribed. Leading from the valve casing 78 is a conduit 88communicating with the conduit 73. Also communicating with the ports ofthe valve casing 78 are conduits 89 and 90 and the latter is connectedto the casing of the 'valve device 37, while the former conduit .89leads to a conventional pressure reducing valve 9'1. A conduit 92 leadsfrom `the reducing `valve 91 to a conventional counterbalancing o1'unloading valve device 93, shown in detail in FIG. 15. This valve devicehas a casing 94 provided with a bore 95 containing a fluid actuatedspool type plunger valve 96 which is constantly urged inwardly by a coilspring 97. A plunger 97 when subjected to pressure fluid serves toactuate the valve 96. The valve casing has passages 98, 99 and 100 towhich certain ofthe several conduits are connected, as later described.Also leading from the pilot operated fluid actuated four-way valvedevice 44 is a conduit 101 connected `to a conventional pressure relayvalve device 102, shown in FIG. 16. This valve device has a casing 1113provided with a bore 104 containing a uid actuated spool type plungervalve 105 urged in one direction by a coil spring 106. The casing hasusual ports connected to the several 'conduits and controlled by thevalve and leading from the casing is a conduit 107 communicating withthe conduit 92;, and a return conduit 168 leads from the valve casingback to the tank 33.

Communicating with the bore containing the slide valve 65 are conduitsi110 and 111 connected to the opposite ends of the sumping andreti-acting cylinders 10, and connected in the conduit 110 is aconventional sequence valve device 112. A conduit 113 leads from thisvalve device to the cylinder 22 of the holding column or jack device 21,while a branched conduit 114 connected to the opposite ends of thecylinder 22 communicates with the conduit 111. A usual return conduitleads from the valve casing back to the tank 33. Communicating with thebore containing the slide valve 66 are conduits 115 and 116, the formerleading to the casing of the counterbalancing or unloading valve device93, while the latter conduit 116 leads to the lower ends of the bores ofthe jib lifting or shear cylinders 15. A conduit 117 connects theconduit 116 with the casing of the valve device 93 and arranged in theconduit 116 between the conduit -117 and the valve box is a`conventional check valve device 118 which permits flow of fluid towardthe cylinders 15 but prevents reverse flow back to the valve box. Areturn conduit 119 leads from the valve device 93 back to the tank, anda conduit 120 controlled by a hand valve 121 may provide a restrictedfiow through the conduit "115 back to the tank, for a purpose to belater described.

The mode of operation of the improved cycling control for effectingautomatically the sumping, swinging, retracting and lowering movementsof the attacking and `disintegrating head or jib is as follows: When thecontinuous miner is disposed at the `working face of the mine vein, asshown diagrammatically in FIG. 8, with the attacking and disintegratinghead or jib in its lowered operating position and automatic control ofthe operating cycle of the head is desired, the handle 3S of the controldevice 37 may be shifted to the left-hand position shown in dotted linesin FIG. 9 and, with the pumps 29 and 30 running, the operator may pressin the push-button 41 of the starting valve device 40 to initiate theautomatic operating cycle.

Sumping As the push-button is held in depressed position, pressure fluidmay flow through conduits 34 and 36, past the valve device 37, andthrough conduit 39, past the valve 40, and through conduit 43 to theleft-hand end of the pilot operated four-way valve device 44, shiftingthe spool valve 47 thereof to the position shown in FG. 10. As shown iniFIG. 10, the conduit 74 is connected to the right-hand exhaust groove48 which communicates with the return conduit 48. Conourrently pressurefluid fiows through conduit 59 to the valve device 50 which is at thistime held depressed by the cam 57 (IFIG. 1l) with the conduit 49 cut `oifrom communication with the conduit shown in FIGS. '10 and 11 pressurefluid may ow through conduits 59, .60 and 73 to the operating cylinderor servornotor 68 for the slide valve 65 of the valve box 63, shiftingthe slide valve to a position to effect fluid supply to the conduit 110.When the slide valve 65 is shifted in the proper direction pressureiiuid may flow through the conduit to the sequence valve device 112,thereby to effect fluid supply to the holding column or jack device Z1to expand the latter and when the column is set rmly between the floorand the room, pressure fluid flowing to the rear ends of the sumpingcylinders 10 effects forward movement of the pistons 11, thereby to sumpthe outer portion of the attacking and disintegrating head or jib intothe mine vein at the floor or pavement level.

Upon initiation of forward movement of the shiftable cam frame 56, theoperator may release the starter button 41, with the cam 57 moved out ofcontact with the roller 55 on the plunger valve 53 so that the spring 54has moved the plunger valve to a position to effect fluid flow throughconduit 49 and conduit 60 to the valve device 44 and the conduits 59 and43 are concurrently connected to exhaust through the valve device 40 andthe return conduit 42 leading back to the tank. When the conduit 43 isconnected to exhaust the slide valve 47 remains in the position shown inFIG. 10.

Shearng As the shiftable cam frame 56 moves forwardly with the head wdapproaches the forward end of its travel, the cam 86 engages the arm 83of the rotary valve 80 so that as the frame 56 completes its forwardmovement the valve 8d3 is rotated to position a cross` port 811 thereinto connect conduit 88 with the conduit 76 thereby to effect fluid supplythrough conduits S8 and 76 to the operating cylinder or servo-motor 69lfor the slide valve 66 of the valve box 63, to effect shifting of theslide valve to a position to effect uid supply through conduit 116, pastthe check valve 11S to the head or jib-lifting cylinders 15 to swing thehead of jib upwardly about its pivot to effect its upward shearing cutbetween the floor and roof. The conduit 75 may then be vented backthrough the valve device 37, conduit 90, past the valve device '77, tothe return conduit 84 leading back to the tank.

Vifhen the attacking and disintegrating head or jib reaches its limit ofupward swing at the `roof level, the pressure in the conduit 116communicating with the lower ends of the bores of the cylinders 15builds up to substantially line pressure and this built-up pressure actsthrough conduits 117 and 107 on the pressure area of the plunger valve105, shifting the latter to a position (toward the -right in FIG. 16) toeffect fluid flow through conduit 101 to the right-hand end of the spoolvalve 47 of the valve device 44, thereby shifting the spool valve 47thereof toward the left to a position (opposite from that shown in FIG.10). This effects iluid ilow through conduit 74 to the operatingcylinder or servomotor 63 for the slide valve 65, and at this time theconduit 73 is vented back through the left-hand exhaust groove 48 of thevalve device 44 to the conduit 48 leading back to the tank. Concurrentlythe conduit 76 is connected back to the tank, past the double rotaryvalve device 77 and through conduits 83, 73 and 48, and since theconduit 75 is `likewise vented through conduit 90, past the rotary valvedevice 77 and return conduit 84, the slide valve 66 is moved by itscentering springs into neutral position exhausting the pressure in theconduit and the portion of the conduit 116 between the check valve 118and the slide valve 66, and as a result the fluid is trapped in thecylinders 15 by the check valve 11S and the valve device 93, holding thehead of jib in its raised retracting position.

Retractng The pressure flowing to the operatingl cylinder or servo- 60.When the valves 47 and 53 assume the positions 75 motor-68 by way ofconduit 74 acts on the piston 67 to shift the slide valve 65 to aposition to effect flow of pressure fluid through conduit 111 to theforward ends of the cylinders to effect rearward movement of the pistons11, thereby to retract the attacking and disintegrating head or jib fromthe mine vein at the roof level.

Lowering The shiftable cam frame 56 moves rearwardly with the retractingpistons 11 and as the latter approach their rearmost positions, the cam37 engages the arm 82 of the rotary valve 80 to rotate the latter to aposition to effect flow of pressure fluid from the conduit 116 betweenthe swing cylinders and the check valve 118, through conduit 117 pastthe valve device 93, through conduit 92 past the valve 91, throughconduit 89 past the valve device 77, through conduit 90, past the thevalve device 3'7, and through conduit 75, to the operating cylinder orservomotor 69 for the slide Valve 66, thereby causing the piston 67 toshift the slide Valve 66 to a position wherein pressure fluid may flowthrough conduit 115 to the lower end of the piston 97 beneath the valve96 (Fig. l5), shifting the latter to a position to effect venting of thejib-lifting or shear cylinders 15 through conduits 117 and 119 back tothe tank. Pressure is established in the conduit 89 as will now beexplained.

The weight of the attacking and disintegrating head or jib duringdownward gravity swing acts on the fluid in the cylinders 15 to providea substantial pressure which is made available through the pressurereducing valve 91 and conduit 89 leading to the double rotary valvedevice 77 and conduit 75 leading to the operating cylinder orservo-motor 69 for the slide valve 66. The fluids flow past this slidevalve and through conduit 115 to the restricted leak conduit 1Z0 createsjust enough pressure acting on the piston 97' to shift the valve of theunloading valve device 93, connecting the conduit 117 to the conduit119. As the disintegrating head or jib is being lowered some fluid isalso being vented from the conduit 11S' through therestriction-providing valve 121 in conduit 120 and upon pressure drop inconduit 115 the plunger valve 96 of the valve device 93 will be movedinwardly by the coil spring 97. This will stop the venting of thepressure fluid in conduit 117 through conduit 119 and the pressure inconduit 117 will then build up again so that fluid is forced throughconduit 92 past the valve 91, conduit 89, valve device 77, conduit 90,valve device 37, conduit 75 to the servomotor cylinder 69 to again moveslide valve 66 into the position to again supply the conduit 115 withpressure fluid and thus again move the plunger valve 96 upwardly so asto vent conduit 117 through conduit 119. When the jib lifting pistons 1Sreach bottom and the head or jib is in its bottom position the pressurein the cylinder 15 becomes dissipated, causing the centering springs ofthe slide valve 66 to move the latter to its neutral position and thepressure in both of the conduits 117 and 11S s exhausted.

When the holding column or jack device 21 is released, the mobile baseof the miner may then be fed forwardly to locate the miner in a newoperating position at the Working face and upon depressing thepush-button 41 of the starting valve device 4l) the operating cycleabove described may be repeated. Since the particular structure and themode of operation of the several valve devices 35, 37, 40, 44, 54), 77,91, 93, 102 and 112 are well known to those skilled in the art and donot per se enter into the present invention, a more comprehensivedescription of the structure and mode of operation of these valvedevices is herein unnecessary.

When it is desired to shift from automatic cycling control to manualcontrol, the valve handle 38 may be turned to the full line right-handposition in FIG. 9, and at that time the valve device 37 is positionedto connect the conduit 75 to the return line leading back to the tank.Thus during manual control both servo-motors 68 and 69 are vented, sothat the slide valves 65 and 66 may readily be shifted to the handcontrols 71.

As a result of this invention, improved automatic cycling control for acontinuous miner is provided wherein the operating cycle of theattacking and disintegrating head or jib is automatically controlled,thereby substantially speeding up the mining operation. By the provisionof the several automatic control valves the sumping, swinging,retracting and lowering movements of the attacking and disintegratinghead or jib may be effected, simply by operating a push-button on theminer, and after the operating cycle is completed the miner isautomatically stopped until the operator again depresses the pushbuttonof the starting valve. The improved automatic cycling control isrelatively foolproof and may be applied to a conventional continuousminer with a minimum of modification of the miner. By the provision ofthe manual control valve for the automatic cycling mechanism theoperating cycle of the attacking and disintegrating head may be effectedmanually as well as automatically, simply by changing the position of acontrol valve. These and other advantages of the invention will beclearly apparent to those skilled in the art.

While there is in this application specifically described one form whichthe invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. in combination, in a continuous miner, a vein-attacking anddisintegrating head for dislodging and disintegrating the mineral of asolid mine vein, fluid operated means for moving said head forwardly tosump the same into the mine vein at the floor level and for retractingsaid head from the vein at the roof level, fluid operated means forswinging said head upwardly between its lowered sumped position and itsraised retracting position, and controlling means for said fluidoperated Vmeans for first sumping said head, then swinging said headupwardly, then retracting said head and finally causing movementof saidhead downwardly back to its initial position, all automatically in adefinite cycle, said controlling means including a fluid actuated valvecontrolled by operation of said fluid operated sumping and retractingmeans and means for subjecting said valve to the action of pressurefluid, said controlling means including a shiftable fluid actuated valveresponsive to the pressure in said fluid actuated swinging means forcontrolling the movements of said rst mentioned fluid actuated valve.

2. In combination, a frame, la support movable back and forth relativeto said frame, a vein-attacking and disintegrating head pivotallymounted on said support to swing in vertical planes, a fluid cylinderfor moving said support forwardly relative to Said frame for sumpingsaid head into the mine vein at the floor level and for retracting saidhead from the vein at the roof level, a fluid cylinder for swinging saidhead upwardly about its pivot, and controlling mechanism for effectingsumping, swinging and retracting movements of said head automatically ina definite cycle, said controlling mechanism including fluid actuatedcontrol means responsive to pressure conditions in said swing cylinderfor automatically effecting operation of said cylinder for retractingsaid head from the mine vein whenever said head reaches its raisedposition, and means for subjecting said control means to the pressure insaid swing cylinder, said controlling mechanism including a fluidactuated unloading Valve for eecting a restricted venting of said swingcylinder to permit swinging of said head downwardly by gravity about itspivot, said control means being responsive to the pressure in said swingcylinder caused by the weight of said head acting on the fluid in saidswing cylinder during such gravity down-swing of said head, the pressureacting on said control means to hold the latter open until said headreaches its limit of down travel.

3. A combination as set forth in claim 2 wherein said control meansincludes a fluid actuated valve whose movement is responsive to thepressure in said swing cylinder for controlling the flow of actuatingpressure from said unloading valve, and means for subjecting said uidactuated valve to the pressure in said swing cylinder.

References Cited in the le of this patent UNITED STATES PATENTS HaydenIan. 30, 1945 Yarmak Aug. 11, 1953 Osterhus et al Ian. 8, 1957 BarrettJan. 8, 1957 FOREIGN PATENTS Germany Nov. 24, 1919 Great Britain Mar.12, 1937

